Pd Active Sites Research Articles

Optimizing H-adsorption affinity on electron-enriched Pdδ- active sites for efficient photocatalytic H2 evolution

Noble metal Pd is a promising H2-evolution cocatalyst and has attracted expansive attention in photocatalytic water splitting. However, the present H2-production rate of Pd cocatalysts is still limited due to its strong hydrogen adsorption on Pd active sites, resulting in poor hydrogen evolution kinetics. In this work, an electron-enriched Pdδ- modulation strategy is developed to weaken the hydrogen adsorption on Pd active sites by producing PdAu alloy, resulting in an increased H2-production rate. In this case, the PdAu homogeneous alloy with a particle size of 9–20 nm is uniformly deposited on the TiO2 surface to produce PdAu-modified TiO2 photocatalysts (TiO2/PdAu). It is found that the prepared TiO2/Pd79Au21 sample achieves the maximal photocatalytic H2-production performance of 31.98 mmol g-1 h−1, which is 1.53 times higher than that of TiO2/Pd photocatalyst. Experimental and theoretical studies show that in addition to the promoted transfer of photogenerated carriers, the PdAu alloy can spontaneously induce the electron transfer from Au to Pd to form electron-enriched Pdδ- sites, which prominently weakens the Pd-Hads bonds and thus improve the H2-production efficiency. This study provides further insight into the rational optimization of active sites to facilitate the design of efficient photocatalysts.

Cerium-optimized platinum-free high-entropy alloy nanoclusters for enhanced ampere-level sustainable hydrogen generation

The incorporation of rare earth (RE) elements into high-entropy alloys (HEAs) as electrocatalysts for hydrogen evolution reaction (HER) shows great potential in addressing the energy crisis. Here, we successfully synthesized cerium (Ce)-tailored PdCeMoCuRu HEA with chemical homogeneity and stability using a facile wet-chemical synthesis strategy. The obtained PdCeMoCuRu HEA provides abundant active metal sites, resulting in superior HER performance compared to state-of-the-art Pt/C. It only requires 12.8 mV to achieve a current density of 10 mA cm−2, which is nearly half that required for Pt/C (24.8 mV). Importantly, it exhibits excellent electrocatalytic durability for 100 hours even under a high current density of 1.0 A cm−2 at the ampere level. Density functional theory (DFT) calculations confirm that the introduction of Ce can modify the electronic configuration and generate synergistic effects around Pd, Cu, and Ru active sites. This work establishes a novel approach for designing efficient RE-tailored HEA electrocatalysts.

Nest-shaped hollow-encapsulated Pd catalyst enhances the catalytic performance of hydrogen peroxide directly synthesizing from hydrogen and oxygen

A well-defined structural morphology can significantly construct a special catalytic micro-reaction environment to enhance the catalytic performance of Pd catalyst in the direct synthesis of hydrogen peroxide from hydrogen and oxygen (DSHP). In this study, SiO2 was used as a rigid template, PdCl2 as the Pd precursor, and dopamine hydrochloride (DA) as the carbon and nitrogen source to synthesize a nest-shaped hollow-encapsulated Pd catalyst named PdMulti@ONHCS. This catalyst was successfully constructed via high-temperature pyrolysis of poly dimethyl diallyl ammonium chloride (PDDA), which generated a blasting effect crucial for this formation. Characterization analysis, catalytic performance evaluation experiment, and molecular dynamics simulation were conducted to explore the structure-performance relationship of PdMulti@ONHCS catalyst in DSHP. Both experimental and simulation results consistently showed that the nest-shaped hollow structure of PdMulti@ONHCS catalyst created a distinctive catalytic microreactor environment with a spatial mass transfer constraint, which was not only conducive to adsorption and enrichment of H2 and O2 at Pd active sites to produce H2O2. In addition, the generated H2O2 can be desorbed from Pd active sites in time and rapidly diffused into the reaction solution, effectively inhibiting the dissociation of species containing OO bonds on the Pd surface, resulting in severe hydrogenation and decomposition side reactions, and improving H2O2 productivity and selectivity.

Kinetics of the CH4/O2 reaction over supported palladium catalysts on K-doped manganite perovskite: Impact of potassium on the nature of Pd-support interface and related reaction mechanisms

The kinetics of the CH4/O2 reaction, occurring on post-combustion catalysts to treat the exhaust gases of natural gas-powered engines, has been investigated in lean conditions on model Pd catalysts supported on K-doped LaMnO3. Experimental and predicted reaction rates have been compared according to a single site on Pd active sites and dual site reaction mechanism on active sites located at the Pd-perovskite interface. Comparisons with a benchmark Pd/LaMnO3 emphasized significant changes induced by thermal aging at 750 °C in wet atmosphere (10 vol% H2O in 5 vol% O2). Indeed, the contribution of the single site mechanism grows on aged Pd/LaMnO3 emphasizing a deterioration of the Pd-LaMnO3 interface. The opposite trend is observed on Pd/La1−xKxMnO3 with kinetics obeying to a single site mechanism on pre-reduced catalyst and then shifting to a quasi-exclusive dual site mechanism after aging. Such kinetic features have been discussed with respect to bulk and surface physicochemical characterization pointing out the key role of potassium in the stability of the Pd-support interface.

Interfacial Push-Pull Dynamics Enable Rapid Had Desorption for Enhanced Formate Electrooxidation.

The electrocatalytic conversion of formate in alkaline solutions is of paramount significance in the realm of fuel cell applications. Nonetheless, the adsorptive affinity of adsorbed hydrogen (Had) on the catalyst surface has traditionally impeded the catalytic efficiency of formate in such alkaline environments. To circumvent this challenge, our approach introduces an interfacial push-pull effect on the catalyst surface. This mechanism involves two primary actions: First, the anchoring of palladium (Pd) nanoparticles on a phosphorus-doped TiO2 substrate (Pd/TiO2-P) promotes the formation of electron-rich Pd with a downshifted d band center, thereby "pushing" the desorption of Had from the Pd active sites. Second, the TiO2-P support diminishes the energy barrier for Had transfer from the Pd sites to the support itself, "pulling" Had to effectively relocate from the Pd active sites to the support. The resultant Pd/TiO2-P catalyst showcases a remarkable mass activity of 4.38 A mgPd-1 and outperforms the Pd/TiO2 catalyst (2.39 A mgPd-1) by a factor of 1.83. This advancement not only surmounts a critical barrier in catalysis but also delineates a scalable pathway to bolster the efficacy of Pd-based catalysts in alkaline media.

Revealing the Origin of Graphene Anchored Single Palladium Atom for Electrochemical CO2 Reduction to Syngas with Tunable CO/H2 Ratios

AbstractPd based catalysts are rare metal‐based catalyst to yield tunable CO/H2 ratios for Fischer‐Tropsch synthesis. How to achieve the co‐production of CO and H2 with as little Pd as possible is extremely meaningful for Cn industry. Recent experiment revealed single Pd atom anchored on graphene exhibits high activity for CO2 electroreduction to syngas, yet the origin of activity and controllable CO/H2 ratios, especially the exact Pd coordination structure, remains elusive. Here we employ grand‐canonical density functional theory to show that Pd−N1, rather than the commonly accepted Pd‐N4, serves as the active center, and the charge‐carrying capability is an effective descriptor. The site with more Pd−C coordination can better submerge in graphene‘s delocalized π electrons for higher charge‐carrying capacity to carry excess charges that occupy Pd 4dz2 orbital and promote electron injection. Importantly, the tunable CO/H2 ratio can be explained with difference in charge‐carrying capability of transition state for *COOH and *H2 formation. This work solves the puzzle of coordinating structure of Pd active site and demonstrates the important role of charge‐carrying capability in electrochemical process, which shall provide a reference for further exploration of efficient electrocatalysts.

Continuous Strain Regulation of Palladium-Gold at the Atomic Level.

Revealing the effect of surface structure changes on the electrocatalytic performance is beneficial to the development of highly efficient catalysts. However, precise regulation of the catalyst surface at the atomic level remains challenging. Here, we present a continuous strain regulation of palladium (Pd) on gold (Au) via a mechanically controllable surface strain (MCSS) setup. It is found that the structural changes induced by the strain setup can accelerate electron transfer at the solid-liquid interface, thus achieving a significantly improved performance toward hydrogen evolution reaction (HER). In situ X-ray diffraction (XRD) experiments further confirm that the enhanced activity is attributed to the increased interplanar spacing resulting from the applied strain. Theoretical calculations reveal that the tensile strain modulates the electronic structure of the Pd active sites and facilitates the desorption of the hydrogen intermediates. This work provides an effective approach for revealing the relationships between the electrocatalyst surface structure and catalytic activity.

Dimensional Reduction of Metal-Organic Frameworks for Photocatalytic Synthesis of Fused Tetracyclic Heterocycles.

Heterogeneous palladium catalysts with high efficiency, high Pd atom utilization, simplified separation, and recycle have attracted considerable attention in the field of synthetic chemistry. Herein, we reported a zirconium-based two-dimensional metal-organic framework (2D-MOF)-based Pd(II) photocatalyst (Zr-Ir-Pd) by merging the Ir photosensitizers and Pd(II) species into the skeletons of the 2D-MOF for the Pd(II)-catalyzed oxidation reaction. Morphological and structural characterization identified that Zr-Ir-Pd with a specific nanoflower-like structure consists of ultrathin 2D-MOF nanosheets (3.85 nm). Due to its excellent visible-light response and absorption capability, faster transfer and separation of photogenerated carriers, more accessible Pd active sites, and low mass transfer resistance, Zr-Ir-Pd exhibited boosted photocatalytic activity in catalyzing sterically hindered isocyanide insertion of diarylalkynes for the construction of fused tetracyclic heterocycles, with up to 12 times the Pd catalyst turnover number than the existing catalytic systems. In addition, Zr-Ir-Pd inhibited the competitive agglomeration of Pd(0) species and could be reused at least five times, owing to the stabilization of 2D-MOF on the single-site Pd and Ir sites. Finally, a possible mechanism of the photocatalytic synthesis of fused tetracyclic heterocycles catalyzed by Zr-Ir-Pd was proposed.

Enhancing Pd Catalytic Activity by Amine Group Modification for Efficient Direct Synthesis of H2O2.

A great deal of research has been carried out on the design of Pd-based catalysts in the direct synthesis of H2O2, mainly for the purpose of improving the H2O2 selectivity by weakening the activation energy on the Pd active site and thus inhibiting the dissociation of the O-O bonds in O2*, OOH*, and HOOH*. However, this often results in insufficient activation energy for the reaction between H2 and O2 on Pd, leading to difficulties in improving both the selectivity and productivity of H2O2 simultaneously. Based on this, this study reports an efficient catalyst composed of amine-functionalized SBA-15-supported Pd. The strong metal-support interaction not only makes the PdNPs highly dispersed with more Pd active sites but also improves the stability of the catalyst. The amine group modification increases the proportion of Pd0, further enhancing Pd activity and promoting the adsorption and conversion of H2 and O2 on Pd, thereby significantly increasing H2O2 productivity. Additionally, the density-functional theory simulation results showed that due to the hydrogen-bonding force between the amine group and H2O2, this particular anchoring effect would make the hydrogenation and decomposition of H2O2 effectively suppressed. Ultimately, both the selectivity and productivity of H2O2 are improved simultaneously.

Decoding Active Sites for Highly Efficient Semihydrogenation of Acetylene in Palladium-Copper Nanoalloys.

Accurately decoding the three-dimensional atomic structure of surface active sites is essential yet challenging for a rational catalyst design. Here, we used comprehensive techniques combining the pair distribution function and reverse Monte Carlo simulation to reveal the surficial distribution of Pd active sites and adjacent coordination environment in palladium-copper nanoalloys. After the fine-tuning of the atomic arrangement, excellent catalytic performance with 98% ethylene selectivity at complete acetylene conversion was obtained in the Pd34Cu66 nanocatalysts, outperforming most of the reported advanced catalysts. The quantitative deciphering shows a large number of active sites with a Pd-Pd coordination number of 3 distributed on the surface of Pd34Cu66 nanoalloys, which play a decisive role in highly efficient semihydrogenation. This finding not only opens the way for guiding the precise design of bimetal nanocatalysts from atomic-level insight but also provides a method to resolve the spatial structure of active sites.

Systematic analysis of dual-functional catalysts for simultaneous CO-NOx reduction: Toward an effective catalyst design strategy

The development of a multifunctional catalyst suitable for application in existing facilities with limited space, with specific emphasis on its capability to concurrently remove CO and NOx is vital for meeting stringent environmental regulations. This is particularly pertinent to industries such as liquefied natural gas-based power plants and multipollutant-emitting industrial facilities. Another important consideration is that the catalyst should operate over a wide temperature range to facilitate its application across various industrial sites. In this study, we synthesized vanadium-based catalysts with a series of noble metals (Pt, Pd, and Au). The V–W–Pd/TiO2 catalyst achieved a simultaneous CO–NOx reduction efficiency greater than 90% in the widest temperature range, 228–321 °C. The excellent catalytic activities resulted from the Pd active sites, which oxidated CO and adsorbed NOx. This enables the catalyst to easily participate in the NH3-SCR reaction and facilitates NOx reduction. Moreover, we systematically analyzed the reaction properties of each catalyst using diffuse reflectance infrared Fourier transform and temperature programmed desorption methods. This enabled the elucidation of the reaction characteristics and competitive adsorption properties of the catalysts.

Catalytic dechlorination of carbon tetrachloride to combustible hydrocarbons by Pd-Fe hydroxides through atomic hydrogen attack and direct electron transfer

Carbon tetrachloride (CT), a common persistent pollutant in groundwater, has attracted widespread attention from environmental researchers. The dechlorination from CT to combustible hydrocarbons not only represents the removal of contaminants, but also offers the possibility of recovering carbon resources from water. In this work, we used the coprecipitation of Fe(II) and Pd(II) to synthesize Pd-Fe hydroxides for the dechlorination of CT. When Pd and Fe dosages were 0.4 and 5 mM respectively, CT with 26 µM concentration can be fast removed within 5 min, and 43.3 % of CH4 and 11.6 % of C2H6 (mol%) were generated after 110 min. The alkaline condition was more conducive to the complete dechlorination of CT comparing with acidic and neutral conditions. During the olation process, Fe(II) as electron donor transferred electrons to Pd(II) to form Pd(0) clusters. Pd(0) active sites act on the binding of CT and transfer electron to H+/H2O to form adsorbed atomic hydrogen (Hads•). The adsorbed CT molecules on the surface of Pd-Fe hydroxides undergo continuous dechlorination to form CH4 and C2H6 through the attack of Hads• and direct electron transfer. In real groundwater applications, CT was rapidly removed, with CH4 and C2H6 yields reaching 24.5 % and 4.6 % (mol%), respectively. Encouragingly, incomplete dechlorinated products, including chloroform and dichloromethane, did not show signs of subsequent rebound even after 60 min. Furthermore, Pd-Fe hydroxides also exhibit resistance to the oxidation effects of dissolved oxygen, which demonstrates the promising application prospects.

Unveiling the roles of distinct active sites over Pd/SSZ-13 for low-temperature NOx adsorption

Pd-based zeolites are attractive candidates for passive NOx adsorbers to reduce NOx emission from vehicle exhausts at low temperature. However, it is not well understood the NO adsorption/desorption mechanism in the presence of H2O and CO, which are constant components in diesel exhaust. In this study, an initial Pd/SSZ-13 sample was treated by reduction in H2 and then oxidation in NO to obtain a hydrophilic Pd/SSZ-13 with mostly Z[Pd2+(OH)] sites, or by thermal aging at 750 °C to prepare a hydrophobic Pd/SSZ-13 dominated by Z2Pd2+ and Z[Pd2+(OH)] sites. The two distinct Pd/SSZ-13 catalysts were characterized by XRD, H2-TPR, 27Al MAS NMR, and in situ DRIFTS spectra of CO adsorption, etc. Furthermore, the NOx adsorption/desorption reaction experiments and in situ DRIFTS studies were carried out on the two Pd/SSZ-13 catalysts under various conditions to explore the role of Z2Pd2+ and Z[Pd2+(OH)] sites in NO adsorption in the presence of H2O or co-existence of H2O and CO. Additionally, the recovery of active Pd sites after NO desorption was studied.

Engineering of local electron properties optimization in single-atom catalysts enabling sustainable photocatalytic conversion of N2 into NH3

Photocatalytic synthesis of ammonia (NH3) from nitrogen (N2) offers a promising strategy for carbon neutrality, as it avoids the energy-intensive and carbon-emitting industrial processes. The exploration of high-efficiency N2 photofixation systems for photocatalytic N2 reduction reaction (pNRR) is critical but it remains a challenge since the lack of rational structural design and atomic-level insights into molecular N2 activation mechanism. Herein, an atomically dispersed single-atom palladium (Pd) active sites decorated oxygen-deficient molybdenum oxide (Pd/MoO3-x) was creatively designed for assessing pNRR performance. Interestingly, the integration of single-atom Pd active sites in MoO3-x can significantly weaken the N≡N bond of adsorbed N2 and effectively lower the activation energy barrier during the pNRR process. This is attributed to the fact that the modified Pd single-atom sites of Pd/MoO3-x play a dominant role in the N2 spontaneous adsorption process as well as possess a remarkable photogenerated electron trapping ability, which could be assisted to inject electrons into N2 antibonding orbital, thus significantly accelerates the reaction kinetics. Consequently, the Pd/MoO3-x photocatalyst reaches an impressive NH3 yield rate of 103.2 μggcat.−1h−1, which is superior to that of pristine MoO3-x (21.2 μggcat.−1h−1) and commercial MoO3 (6.5 μggcat.−1h−1), respectively. The present study not only creates a reliable approach to expand efficient N2 photofixation system under mild conditions through the fabrication of atomically dispersed monometallic active sites, but also offers atomic-level insights into the underlying mechanism of pNRR catalytic process.

Construction of imide‐linked covalent organic frameworks with palladium nanoparticles for oxygen reduction reaction

AbstractCovalent organic frameworks (COFs) have been widely employed as electrocatalysts for oxygen reduction reaction (ORR) due to their diverse and tunable skeletons and pores. However, their electrocatalytic activity was limited due to the lack of highly active catalytic sites. In this work, we have first immobilized palladium nanoparticles (NPs) into the crystal, porous, and stable imide‐linked COF for ORR. The newly designed COF had pyridine linkers with imide‐linkages in the frameworks serving as the binding sites to anchor Pd sites, and the high surface area and open pore channels provide fast mass transport pathway to the active Pd sites, which contributed highly active performance in ORR. And the designed catalyst delivered onset potential and the half‐wave potential of COF‐Pd of 0.97 and 0.83 V, with a limited current density of 6.1 mA cm−2, respectively. This work provides us insights into developing high crystalline COFs with metal NPs in electrocatalytic systems.

The interaction between Pd/CeO2 crystal surface and electric field: Application to complete oxidation of methane

Pd/CeO2 with different crystal faces can significantly affect the methane oxidation process, but the catalytic behavior in electric field is not clear yet. The supported Pd/CeO2 with rod, octahedral and cubic morphologies were synthesized by hydrothermal method, and their methane oxidation efficiency in electric field was measured. The structure of Pd/CeO2 and reaction mechanism in electric field were investigated by XRD, BET, XPS, H2-TPR, TEM and in situ DRIFTs. Studies show that the synergistic effect between electric field and (111) crystal plane in octahedral CeO2 is the strongest and (110) in rod CeO2 is the main active restraint crystal plane. The Pd atoms on the surface of Pd/CeO2-oct are exposed to the most amount of Pd atoms and the main Pd nanoparticles are present. Pd species on CeO2-cube and CeO2-rod surface with relatively low activity exist mainly in the form of Pd2+ and Pd4+, whereas Pd0 and Pd2+ on the Pd/CeO2-oct surface are more favorable for CH4 oxidation in the catalytic cycle. Pd4+ is inactive for CH4 oxidation. In addition, H migration from Pd active site to the support induced by hydrogen spillover can enhance the oxidation activity of CH4 in electric field. The conversion of carbonate/hydrogencarbonate to formate is an advantageous step in the methane oxidation process, with the active sequence being octahedral (111) > cubic (100) > rod (110) faces in/without electric field.

Pd-Mn/NC Dual Single-Atomic Sites with Hollow Mesopores for the Highly Efficient Semihydrogenation of Phenylacetylene.

The direct pyrolysis of metal-zeolite imidazolate frameworks (M-ZIFs) has been widely recognized as the predominant approach for synthesizing atomically dispersed metal-nitrogen-carbon single-atom catalysts (M/NC-SACs), which have exhibited exceptional activity and selectivity in the semihydrogenation of acetylene. However, due to weak adsorption of reactants on the single site and restricted molecular diffusion, the semihydrogenation of large organic molecules (e.g., phenylacetylene) was greatly limited for M/NC-SACs. In this work, a dual single-atom catalyst (h-Pd-Mn/NC) with hollow mesopores was designed and prepared using a general host-guest strategy. Taking the semihydrogenation of phenylacetylene as an example, this catalyst exhibited ultrahigh activity and selectivity, which achieved a turnover frequency of 218 molC═CmolPd-1 min-1, 16-fold higher than that of the commercial Lindlar catalyst. The catalyst maintained high activity and selectivity even after 5 cycles of usage. The superior activity of h-Pd-Mn/NC was attributed to the 4.0 nm mesopore interface of the catalyst, which enhanced the diffusion of macromolecular reactants and products. Particularly, the introduction of atomically dispersed Mn with weak electronegativity in h-Pd-Mn/NC could drive the electron transfer from Mn to adjacent Pd sites and regulate the electronic structure of Pd sites. Meanwhile, the strong electronic coupling in Pd-Mn pairs enhanced the d-electron domination near the Fermi level and promoted the adsorption of phenylacetylene and H2 on Pd active sites, thereby reducing the energy barrier for the semihydrogenation of phenylacetylene.

Efficient catalytic oxidation of VOCs by a Pd-Pt/SiO2 catalyst: The cooperative catalysis of dual metal sites

Volatile organic compounds (VOCs) are one of the main pollutants produced in industrial processes. Catalytic oxidation is an effective method to eliminate VOCs, and the key lies in designing efficient metal catalyst. In this work, Pd-Pt/SiO2 bimetallic catalysts were designed and prepared by the immobilization method, and their performances for toluene oxidation were evaluated. The addition of Pt into the catalyst elevated markedly the reduction of Pd active sites, leading to abundant electron-deficient Pd0 and electron-rich Pt0 in the Pd2Pt1 catalyst, which were confirmed by TEM, CO pulse adsorption and in-situ XPS. As revealed by O2-TPD and toluene-TPD characterization, the cooperative effect of electron-deficient Pd0 and electron-rich Pt0 in Pd2Pt1 catalyst facilitated the activation of O2 and toluene, thus enhanced greatly its activity. A conversion of 90% (T90) for toluene was achieved over Pd2Pt1 catalyst at 165 ℃, and the apparent activation energy (Ea) over Pd2Pt1 catalyst was lower than that over other Pd-Pt bimetallic and monometallic Pd or Pt catalysts. Additionally, the reaction mechanism was studied by In-situ DRIFTS, the results showed that the toluene oxidation passed successively benzyl alcohol, benzaldehyde, benzoic acid and maleic anhydride, then maleic anhydride was further oxidized to CO2 and water.

TiO2-based Pd/Fe bimetallic modification for the efficient photothermal catalytic degradation of toluene: The synergistic effect of ∙O2– and ∙OH species

The construction of photothermal catalysts to provide advanced oxidation ability and stability is a great challenge for eliminating volatile organic compounds (VOCs) during the photothermal catalytic process. Herein, a bimetallic modification method was proposed to synthesize Pd/Fe-TiO2. Under ultraviolet–visible (UV–Vis) light irradiation with the intensity of 610 mW/cm2, the optimal 0.7 wt% Pd/0.4 wt% Fe-TiO2 catalyst of which surface was detected at the temperature of 165 °C can achieve a toluene conversion of 94 % and a CO2 yield of 87 %, respectively. Based on the results of in-situ DRIFTS, quasi-situ EPR, XPS, and O2-TPD tests, it was found that two distinct types of Pd and Fe active sites not only generated reactive oxygen species (ROS) but also adsorbed toluene and intermediate species, which promoted the degradation of toluene. It is proposed that there be an electron transfer behavior between Fe and Pd nanoparticles, resulting in a synergistic interaction of the two metals. This study shows that creating bimetallic modification catalysts is an efficient method for eliminating VOCs through photothermal catalysis.

Boosting hydrogen evolution performance of nanoporous Fe-Pd alloy electrocatalyst by metastable phase engineering

Nanoporous Fe-Pd alloy with metastable face-centered cubic (fcc Fe-Pd) phase is prepared by electrochemical dealloying as an electrocatalyst for hydrogen evolution reaction (HER). The nanoporous fcc Fe-Pd alloy achieves an overpotential of 58 mV at 10 mA cm−2 in 1 M KOH, outperforming those of stable body-centered cubic Fe-Pd alloy (bcc Fe-Pd) and commercial Pt/C catalyst. Density functional theory calculation reveals that the metastable fcc structure can tailor the coordination environment and electronic structure of Pd active sites in Fe-Pd alloy. As a result, the d‐band center of Pd active site shifts away from the Fermi level, which weakens the Pd-H interaction and reduces the energy barrier of water dissociation. In addition, the fcc Fe-Pd exhibits good mechanical properties, which maintains the catalytic performance in the deformation state. This work broadens the idea for designing and preparing HER catalysts via metastable phase structure design.